why is the suicide rate higher in males than in females almost uniformly worldwide?

A main reason rates of completed suicide are higher in males than females in most of the world is that males choose to use - and have greater access and opportunity to use - the most violent and effective means of suicide: firearms, hanging, asphyxiation, jumping from heights, throwing themselves in front of fast-moving motor vehicles.

In the US, most males who commit suicide do by gunshot - specifically by shooting themselves in the head. Most women who've considered suicide would not even attempt to do so by firearms because of the bloody mess it would leave. Women do not feel they have the right to leave such a horrible mess for someone else to discover and clean up. Which might explain why most women eschew the other violent routes as well.

Suicide statistics show that while men are two to four times more likely than women to die by suicide, women are roughly three times more likely than men to attempt suicide, and much more likely to have suicidal thoughts and urges.

Mothers seem less likely to commit suicide than fathers. Not necessarily because suicidal mothers are any less distressed and despairing than fathers, but because they are more cognizant of, and concerned with, the impact of parental suicide on their children - and their children's children.

Although it's generally true that males die of suicide at higher rates than females, it's not universally true. In China, for example, females long have had higher suicide rates than males, particularly in rural areas.

A notable stat is that "Suicide ranks as the number one cause of mortality in young girls between the ages 15 and 19 years globally."

http://www.indianjpsychiatry.org/article.asp?issn=0019-5545;year=2015;volume=57;issue=6;spage=233;epage=238;aulast=Vijayakumar